package leetcode101.search_problem.dfs;

/**
 * @author Synhard
 * @version 1.0
 * @Class leetcode101.graph.Code1
 * @Description  695. Max Area of Island (Easy)
 * Given a non-empty 2D array grid of 0's and 1's, an island is a group of 1's (representing land)
 * connected 4-directionally (horizontal or vertical.)
 * You may assume all four edges of the grid are surrounded by water.
 *
 * Find the maximum area of an island in the given 2D array. (If there is no island, the maximum area is 0.)
 *
 * Example 1:
 *
 * [[0,0,1,0,0,0,0,1,0,0,0,0,0],
 *  [0,0,0,0,0,0,0,1,1,1,0,0,0],
 *  [0,1,1,0,1,0,0,0,0,0,0,0,0],
 *  [0,1,0,0,1,1,0,0,1,0,1,0,0],
 *  [0,1,0,0,1,1,0,0,1,1,1,0,0],
 *  [0,0,0,0,0,0,0,0,0,0,1,0,0],
 *  [0,0,0,0,0,0,0,1,1,1,0,0,0],
 *  [0,0,0,0,0,0,0,1,1,0,0,0,0]]
 * Given the above grid, return 6. Note the answer is not 11, because the island must be connected 4-directionally.
 * Example 2:
 *
 * [[0,0,0,0,0,0,0,0]]
 * Given the above grid, return 0.
 * Note: The length of each dimension in the given grid does not exceed 50.
 * @tel 13001321080
 * @email 823436512@qq.com
 * @date 2021-03-30 16:36
 */
public class Code1 {
    public static void main(String[] args) {
//        int[][] nums = new int[][]{
//                {0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0},
//                {0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
//                {0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
//                {0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0},
//                {0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0},
//                {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0},
//                {0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
//                {0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0}
//        };
        int[][] nums = new int[][]{
                {1,1,0,0,0},
                {1,1,0,0,0},
                {0,0,0,1,1},
                {0,0,0,1,1}
        };
        System.out.println(maxAreaOfIsland(nums));
    }

    public static int maxAreaOfIsland(int[][] grid) {
        if (grid == null) {
            return 0;
        }
        int max = 0, temp;
        for (int i = 0; i < grid.length; i++) {
            for (int j = 0; j < grid[i].length; j++) {
                if (grid[i][j] == 1) {
                    temp = find(grid, i, j);
                    max = Math.max(temp, max);
                }
            }
        }
        return max;
    }
    public static int find(int[][] grid, int i, int j) {
        if (i < 0 || i > grid.length - 1 || j < 0 || j > grid[i].length - 1 || grid[i][j] != 1) {
            return 0;
        }
        grid[i][j] = 0;
        int right = find(grid, i, j + 1);
        int up = find(grid, i - 1, j);
        int left = find(grid, i, j - 1);
        int down = find(grid, i + 1, j);
        return 1 + right + up + left + down;
    }

}
